1. Field of the Invention
The present invention relates generally to an electrical connector; particularly, the present invention relates to an electrical connector of decreasing the crosstalk coupling over the full frequency range and enhancing the signal quality.
2. Description of the Prior Art
In general, high frequency signals are transmitted through connecting cables and connectors, wherein the connector has a plug and a jack. Particularly, the plug includes a plurality of metal wires, which are arranged in parallel. Please refer to FIG. 1; FIG. 1 is a schematic view of a partial circuit of the plug. As shown in FIG. 1, the plug 11 includes a first conducting wire 12, a second conducting wire 13, a third conducting wire 14, and a fourth conducting wire 15, wherein the terminal resistor 25 is connected with the first conducting wire 12 and the fourth conducting wire 15 in series; the terminal resistor 34 is connected with second conducting wire 13 and the third conducting wire 14 in series. It is noted that the first conducting wire 12 and the fourth conducting wire 15 are a differential signal pair, and the second conducting wire 13 and the third conducting wire 14 are another differential signal pair.
In practical applications, the high frequency signals are respectively transmitted in the first, second, third, and fourth conducting wires 12 to 15. However, because the spacing between the conducting wires is very small, the high frequency signals of different conducting wires will generate crosstalk coupling. Particularly, the crosstalk coupling exists in the circuit as coupling capacitor, coupling inductor, or coupling resistor, especially as coupling capacitor. As shown in FIG. 1, the coupling capacitor 16 exists between the first conducting wire 12 and the second conducting wire 13; the coupling capacitor 17 exists between the first conducting wire 12 and the third conducting wire 14; the coupling capacitor 18 exists between the second conducting wire 13 and the fourth conducting wire 15; the coupling capacitor 19 exists between the third conducting wire 14 and the fourth conducting wire 15. In addition, once the transmission rate of high frequency signal increases, the values of the coupling capacitors 16 to 19 will also increase to affect the integrity of the high frequency signals.
It is noted that researchers usually utilize the compensation vector method to decrease the crosstalk coupling. In practical applications, the compensation vector method will cause the phase difference between the vectors, so that the researchers need to utilize additional compensation vector to cancel the phase difference. However, the compensation vector method merely decreases the crosstalk of certain frequency or narrow-band region and hard to solve the crosstalk coupling problem of broadband region.
Please refer to FIG. 2; FIG. 2 is a diagram of the crosstalk coupling magnitude of the plug before and after compensation. As shown in FIG. 2, the plug crosstalk coupling magnitude 11A of high frequency is higher than that of low frequency. In addition, the compensated crosstalk coupling magnitude 11B is more effective in lower frequency (0˜200 MHz), but hard to decrease the crosstalk coupling magnitude in high frequency (300˜500 MHz).
For the above reasons, it is an object to design an electrical connector for decreasing the crosstalk coupling over the full frequency range.